Fast charge apparatus for a battery

ABSTRACT

A fast charge system 20 including a fast charge composite 60 and a secondary battery 22 enables the secondary battery 22 to be charged in less time than is possible with traditional charging means. The fast charge composite 60 includes a separator 62 of cellulose wetted with a second electrolyte 64 that contains third ions 94 having a positive charge and fourth ions 96 having a negative charge and contacting the adjacent electrode 32, 46 of the secondary battery 22. A fast charge layer 30 of thermally expanded graphite is disposed adjacent and parallel to the separator 62. A second electrical power PFC, which may be greater than a maximum charging power PMAX transferred through traditional charging, is transferred as a function of a second voltage V2 applied between the fast charge layer 30 and the battery lead 34, 50 of the adjacent electrode 32, 46, which causes the third ions 94 and the fourth ions 96 to migrate through the separator 62 to cause the secondary battery 22 to become charged.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of continuation-in-part U.S. patent application Ser. No. 14/607,530, filed Jan. 28, 2015 which claims the benefit of U.S. patent application Ser. No. 14/539,448 filed Nov. 12, 2014, which claims the benefit of provisional application No. 61/903,145 filed Nov. 12, 2013.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates to a fast charge composite combined with a secondary battery for charging the secondary battery.

2. Description of the Prior Art

It is generally known to construct batteries as a stack of layers, with a cathode sandwiched with the membrane and disposed in spaced and parallel relationship with the anode and an electrolyte impregnating the membrane to carry an ion migration through the membrane. An example of such a battery is shown in U.S. Patent Application 2009/0142668.

It is also known to construct a battery as a stack of layers that form a plurality of electrochemical cells which are connected in parallel or in series. An example of such a battery construction is shown in U.S. Patent Application No. 2012/0058380.

Secondary battery cells that use an electrolyte to convey first ions having a positive charge and second ions having a negative charge between anode and cathode electrodes are well known. An example of such a battery is shown in U.S. Pat. No. 4,707,423.

Secondary battery cells are typically charged using a traditional charging means of applying a first voltage between the anode and the cathode to cause a first current to flow therebetween. An example of such charging is described in U.S. Pat. No. 7,489,107.

It is also well know that a secondary battery may only be recharged with a maximum charging power that is a function of the first voltage between the anode and the cathode times the first current therebetween and applied over a first time interval. There are two main types of damage to battery cells that result from application of power greater than the maximum charging power and cause a substantial loss in capacity. The first main type of damage results from overheating, which causes damage the battery cell through melting and/or the production of gasses (e.g. through boiling the electrolyte). Eventually, overheating damage can cause a short circuit between the electrodes. The second main type of damage is plating, also known as deposition, which occurs with intercalation electrodes that accept ions within a crystalline lattice structure. During normal operation, ions are chemically inserted into the intercalation electrode, where they react with the electrode, trapping the metallic products of the reaction inside of the lattice structure. However, when a power greater than the maximum charging power is applied, ions will react on the surface of an intercalation electrode and cause a metallic layer to form or to be plated on that surface. The formation of that metallic layer is uneven and can create needle-like dendrite structures that extend into the membrane, which can eventually short-circuit the battery cell.

U.S. Pat. No. 6,117,585 to Anani et al. discloses a hybrid energy storage device constructed as a stack of layers, with two electrode layers and a first electrolyte forming a battery. A second electrolyte, sandwiched between a third electrode and one of the battery electrodes, forms an electrolytic capacitor. The Anani et al. '585 device requires an external conductor to directly connect the non-adjacent battery electrode to the capacitor electrode.

SUMMARY OF THE INVENTION

The invention provides for a fast charge composite with a second electrolyte that includes third ions having a positive charge and fourth ions having a negative charge. The fast charge composite is disposed adjacent to and contacting one of the electrodes of a secondary battery, which is the adjacent electrode, and the remaining electrode of the secondary battery is the remote electrode, which is electrically isolated from the fast charge composite. The fast charge composite is responsive to application of a second electrical power, which is greater than the maximum charging power that can be applied to the secondary battery using the traditional charging means of applying a first voltage between the electrodes of the secondary battery to induce a first current therebetween. The second electrical power is a function of a second voltage between the fast charge composite and the adjacent electrode multiplied by the second current therebetween and applied over a second time interval. The application of the second electrical power causes the third ions and the fourth ions to migrate between the adjacent electrode and the fast charge composite to change the electrochemical potential of the adjacent electrode, which enables the secondary battery to store the predetermined amount of electrical energy in a second time interval that is shorter than the first time interval that it would take using the traditional charging means at or below the maximum charging power. In other words, the battery can be charged to its capacity in a shorter time using the fast charge composite than is possible using traditional charging means.

The invention also provides for a method of constructing such a fast charge composite with a second electrolyte, including: dissolving AlCl₃ in ethanol to create a background solution, combining the background solution with glycerol to make a second electrolyte including third ions having a positive charge and fourth ions having a negative charge, and wetting a separator of electrically insulating material with the second electrolyte.

Advantages of the Invention

The invention in its broadest aspect provides a fast charge composite that allows a secondary battery to store a predetermined amount of electrical energy in less time than is possible using the traditional charging means of applying a first voltage and a first current between the battery leads.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a schematic cut-away view of a secondary battery with a fast charge composite disposed adjacent a cathode layer of a secondary battery.

FIG. 2 is a schematic cut-away view of a secondary battery with a fast charge composite disposed adjacent an anode layer of a secondary battery.

FIG. 3 is a cut-away top view of a secondary battery with a fast charge composite disposed below and adjacent a cathode layer of a secondary battery.

FIG. 4 is a schematic of secondary battery being charged through traditional means and showing the movement of ions and conventional (positive) current flow.

FIG. 5 is a schematic of a fast charge system with a fast charge composite disposed adjacent a cathode layer and showing the movement of ions and conventional (positive) current flow while charging the secondary battery using the fast charge composite and while discharging the secondary battery.

DESCRIPTION OF THE ENABLING EMBODIMENT

Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a fast charge system 20 including a secondary battery 22 with a capacity to store a predetermined amount of electrical energy is disclosed. The term “secondary battery” refers to an electrochemical energy storage device that is capable of being recharged.

As shown in the figures, the secondary battery 22 includes a pair of electrodes 32, 46 including an anode layer 32 and a cathode layer 46 extending in parallel and spaced relationship to one another.

The anode layer 32 consists of 99.4 to 99.9 wt % of solid Aluminum of 99.95% purity and 0.1 to 0.6 wt % of Indium with first rectangular borders to define a first length of 1.2 cm, a first width of 1.7 cm, and a first thickness of 0.1 mm. A negative battery lead 34 of electrically conductive material is in electrical contact with the anode layer 32 for conducting electrical current with external circuitry for charging or discharging the secondary battery 22. The negative battery lead 34 could also serve as a point of connection to another battery cell as part of a multi-cell battery device. The negative battery lead 34 could be a wire, pad, terminal, or any other suitable means of making an electrical connection.

The anode layer 32 is attached in electrical contact with the negative battery lead 34 using an electrically conductive cement 36 that includes particles 92 containing metal. Examples of such cements 36 are Two Part Conductive Silver Paint (Part No. 12642-14), sold by Electron Microscopy Sciences and Solder-It Aluminum Solder Paste, sold by SOLDER-IT, INC. of Pleasantville, N.Y.

The cathode layer 46 has a second rectangular border with a second length of 1.4 cm, a second width of 1.9 cm, and a second thickness of 0.1 mm. The cathode layer 46 includes a carrier sheet 48 of cellulose and an electroactive layer 28 integrated within and disposed upon the carrier sheet 48 on the side facing the anode layer 32. In other words, the electroactive layer 28 coats the surface and extends into the structure of the carrier sheet 48. The electroactive layer 28 of the cathode layer 46 contains a host lattice 54 that defines a plurality of voids 56 and includes a conjugated system with delocalized π electrons. A conjugated system is defined as a system of connected p-orbitals containing delocalized electrons in chemical compounds. More specifically, the conjugation is the overlapping of one p-orbital with another across adjacent single (sigma) bonds. One such compound that has such a conjugated system is graphite. Other compounds such as, but not limited to, polyaniline and polyconjugated linear hydrocarbon polymers also include conjugated systems with overlapping p-orbitals.

A positive battery lead 50 containing thermally expanded graphite is electrically connected to the electroactive layer 28 of the cathode layer 46 for conducting electrical current with external circuitry for charging and/or discharging the secondary battery 22. An adhesive 52 containing graphite attaches the electroactive layer 28 to the positive battery lead 50 and conducts electrical current therebetween. One such positive battery lead 50 comprises thermally expanded graphite foil 66. An alternative positive battery lead 50 comprises a rod of graphite with a diameter of 0.1 mm. The positive battery lead 50 could also serve as a point of connection to another battery cell as part of a multi-cell battery device. The positive battery lead 50 could include a wire, pad, terminal, or any other suitable means of making an electrical connection. However, conductors of metal should not be placed in direct contact with the host lattice 54 of the cathode layer 46 because the metal can migrate into the host lattice 54 and interfere with the functionality of the cathode layer 46 in charging and discharging the secondary battery 22.

A dopant 58 containing Aluminum Alcoholate and Aluminum Glycerate is bonded to the conjugated system of the host lattice 54 to alter the electrochemical properties of the electroactive layer 28 of the cathode layer 46 to increase the rate of the reactions with the first ions 24 and the second ions 26 for charging and discharging the secondary battery 22. The dopant 58 is also intercalated in the host lattice 54 so that particles 92 of the dopant 58 are embedded in the voids 56 of the host lattice 54.

A membrane 38 of cellulose having a third thickness 40 of 0.08 mm and defining a plurality of pores 42 is sandwiched between the anode layer 32 and the cathode layer 46 for providing electrical insulation and defining a first voltage V₁ therebetween. The membrane 38 is an electrical insulator, but is permeable to dissolved ions.

The membrane 38 is wetted with a first electrolyte 44 so the first electrolyte 44 impregnates the pores 42 of the membrane 38. The first electrolyte 44 includes first ions 24 that contain Aluminum and have a positive charge. The first electrolyte 44 also includes second ions 26 that contain Aluminum and have a negative charge. The first electrolyte 44 is damaged by application of a first voltage V₁ greater than a predetermined maximum voltage V_(MAX).

An excess ion migration is carried by the first electrolyte 44 through the membrane 38 in response to the application of a first current I₁ between the positive battery lead 50 and the negative battery lead 34 that is greater than a predetermined maximum current I_(MAX).

A maximum charging power P_(MAX) is defined as the first voltage V₁ times the first current I₁, with either the first voltage V₁ being greater than the predetermined maximum voltage V_(MAX) or the first current I₁ being greater than the predetermined maximum current I_(MAX).

A secondary battery may be charged with a power less than the maximum charging power P_(MAX) and applied over a first time interval T₁ as is the case with the traditional means of charging a secondary battery 22, shown schematically in FIG. 4. Application of power in excess of the maximum charging power P_(MAX), between the between the positive battery lead 50 and the negative battery lead 34 can cause irreversible damage to the first electrolyte 44 and/or the membrane 38 and/or either of the electrodes 32, 46, which substantially reduces the capacity of the secondary battery 22.

The first electrolyte 44 consists essentially of glycerol and first ions 24 containing Aluminum and having a positive charge, and second ions 26 containing Aluminum and having a negative charge. The first ions 24 include [Al(ClO₄)₂·{C₃H₅(OH)₃}₂]⁺, and the second ions 26 include [Al(ClO₄)₄]⁻. The first ions 24 and the second ions 26 migrate between and react with the anode layer 32 and the cathode layer 46 to charge and discharge the secondary battery 22.

A fast charge composite 60 overlies and contacts one of the electrodes 32, 46 of the secondary battery 22. The fast charge composite 60 has a third rectangular border with a third length and a third width that are between those of the first rectangular border of the anode layer 32 and the second rectangular border of the cathode layer 46.

The fast charge composite 60 includes a separator 62 of cellulose that is impregnated with a second electrolyte 64 that includes third ions 94 containing Aluminum and having a positive charge. The second electrolyte 64 also includes fourth ions 96 containing Aluminum and having a negative charge. The separator 62 is disposed parallel to and contacting one of the electrodes 32, 46, which is designated as the adjacent electrode 32, 46. The other one of the electrodes 32, 46 that is not in contact with the separator 62 is designated as the remote electrode 32, 46 and is electrically isolated from the fast charge layer 30. The separator 62 is an electrical insulator, but is permeable to dissolved ions.

The fast charge composite 60 also includes a fast charge layer 30 comprising foil 66 of thermally expanded graphite which is disposed adjacent and parallel to the separator 62 so that the separator 62 is sandwiched between the adjacent electrode 32, 46 and the fast charge layer 30. A fast charge lead 68 of electrically conductive material is electrically connected to the fast charge layer 30 for the application of second electrical power P_(FC), which is greater than the maximum charging power P_(MAX) which can be applied between the battery leads 34, 50.

The second electrical power P_(FC) is a function of a second voltage V₂ between the fast charge lead 68 and the battery lead 34, 50 of the adjacent electrode 32, 46 times a second current I₂ that flows through an external circuit between the fast charge lead 68 and the battery lead 34, 50 of the adjacent electrode 32, 46 and applied over a second time interval T₂.

The second electrical power P_(FC) causes the third ions 94 and the fourth ions 96 to migrate through the separator 62 between the adjacent electrode 32, 46 and the fast charge layer 30 to change the electrochemical potential of the adjacent electrode 32, 46 and to cause the secondary battery 22 to store the predetermined amount of electrical energy in a shorter second time interval T₂ than the first time interval T₁ when subjected at or below the maximum charging power P_(MAX) by traditional charging means. In other words, it is possible to charge the secondary battery 22 using the fast charge composite 60 in less time than is possible through traditional charging by applying a first voltage V₁ and a first current I₁ between the battery leads 34, 50. FIG. 5 is a schematic representation of the application of the second electrical power P_(FC) to the fast charge layer 30 by application of the second voltage V₂ and the second current I₂. FIG. 5 also shows the secondary battery 22 transferring power into a resistive load connected between the battery leads 34, 50 at the same time as the secondary battery 22 is being charged using the fast charge composite 60.

The adjacent electrode 32, 46 must be permeable to the third ions 94 and the fourth ions 96. More specifically, a sufficient number of the third ions 94 and the fourth ions 96 must be able to penetrate within the adjacent electrode 32, 46 in response to the application of the second voltage V₂, to cause a sufficient change in the electrochemical potential of the adjacent electrode 32, 46 that enables the secondary battery 22 to store the predetermined amount of electrical energy. A cathode layer 46 that contains a host lattice 54 having a conjugated system with delocalized π electrons may be used as the adjacent electrode 32, 46. Alternatively, an anode layer 32 may be used as the adjacent electrode 32, 46. Such an anode layer 32 may be formed, for example, as an open-cell foam or a solid of particles 92 or granules bound together.

Because of the electrical isolation between the remote electrode 32, 46 and the fast charge composite 60, the second voltage V₂ can be different than the first voltage V₁. This means that it is possible to apply a second voltage V₂ that is in excess of the maximum voltage V_(MAX), which would cause damage to the first electrolyte 44 and/or the membrane 38 and/or either of the electrodes 32, 46 if it were to be applied between the electrodes 32, 46.

In one embodiment, the adjacent electrode 32, 46 is the cathode layer 46, and the remote electrode 32, 46 is the anode layer 32, and each of which is electrically isolated from the fast charge layer 30.

In a second, alternative embodiment, the adjacent electrode 32, 46 is the anode layer 32 and the remote electrode 32, 46 is the cathode layer 46, and each of which is electrically isolated from the fast charge layer 30.

The present invention also provides a method for constructing a fast charge composite 60 combined with a secondary battery 22.

The method includes the steps of: stacking a separator 62 of electrically insulating material upon and parallel to either the anode layer 32 or the cathode layer 46 rendering it the adjacent electrode 32, 46, stacking a fast charge layer 30 of thermally expanded graphite foil 66 upon and parallel to the separator 62 so the separator 62 is disposed between the and the fast charge layer 30, and attaching a fast charge lead 68 in electrical contact with the fast charge layer 30 with a conductive adhesive 52 of graphite paint.

The method includes steps for producing a second electrolyte 64, including: dissolving AlCl₃ powder in ethanol to saturation to create a background solution 78, combining 40 wt % of the background solution 78 with 60 wt % of glycerol to make a binary solvent 80, grating 1 cm³ of 99.4 to 99.9 wt % of Aluminum of 99.95% purity and 0.1 to 0.6 wt % of Indium to make filings 82 with an equivalent surface area of 20 to 30 cm², immersing the filings 82 in 150 to 200 ml of the binary solvent 80 until the filings 82 have dissolved to produce a second electrolyte 64 that includes third ions 94 that contain Aluminum and have a positive charge and fourth ions 96 that contain Aluminum and have a negative charge.

The method concludes with the step of wetting the separator 62 with the second electrolyte 64.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. That which is prior art in the claims precedes the novelty set forth in the “characterized by” clause. The novelty is meant to be particularly and distinctly recited in the “characterized by” clause whereas the antecedent recitations merely set forth the old and well-known combination in which the invention resides. These antecedent recitations should be interpreted to cover any combination in which the inventive novelty exercises its utility. The use of the word “said” in the apparatus claims refers to an antecedent that is a positive recitation meant to be included in the coverage of the claims whereas the word “the” precedes a word not meant to be included in the coverage of the claims. In addition, the reference numerals in the claims are merely for convenience and are not to be read in any way as limiting.

ELEMENT LIST Element Symbol Element Name 20 fast charge system 22 secondary battery 24 first ions 26 second ions 28 electroactive layer 30 fast charge layer 32 anode layer 34 negative battery lead 36 cement 38 membrane 40 third thickness 42 pores 44 first electrolyte 46 cathode layer 48 carrier sheet 50 positive battery lead 52 adhesive 54 host lattice 56 voids 58 dopant 60 fast charge composite 62 separator 64 second electrolyte 66 foil 68 fast charge lead 78 background solution 80 binary solvent 82 filings 92 particles 94 third ions 96 fourth ions I₁ first current I₂ second current I_(MAX) maximum current P_(FC) second electrical power P_(MAX) maximum charging power T₁ first time interval T₂ second time interval V₁ first voltage V₂ second voltage V_(MAX) maximum voltage 

What is claimed is:
 1. A method for constructing a fast charge composite (60) combined with secondary battery (22) having an anode layer (32) and a cathode layer (46), said method comprising; stacking a separator (62) of electrically insulating material upon and parallel to one of said anode layer (32) and said cathode layer (46) rendering it an adjacent electrode (32, 46), stacking a fast charge layer (30) upon and parallel to the separator (62) with the separator (62) disposed between said adjacent electrode (32, 46) and said fast charge layer (30), and characterized by, dissolving AlCl₃ in ethanol to create a background solution (78), combining the background solution (78) with glycerol to produce a second electrolyte (64) including third ions (94) having a positive charge and including fourth ions (96) having a negative charge, wetting the separator (62) with the second electrolyte (64).
 2. A method for constructing a fast charge composite (60) combined with a secondary battery (22) having an anode layer (32) and a cathode layer (46), said method comprising; stacking a separator (62) of electrically insulating material upon and parallel to one of said anode layer (32) and said cathode layer (46) rendering it an adjacent electrode (32, 46), stacking a fast charge layer (30) of thermally expanded graphite upon and parallel to the separator (62) with the separator (62) disposed between the adjacent electrode (32, 46) and the fast charge layer (30), attaching a fast charge lead (68) in electrical contact with the fast charge layer (30) with an adhesive (52) of graphite paint, and characterized by, dissolving AlCl₃ powder in ethanol to saturation to create a background solution (78), combining 40 wt % of the background solution (78) with 60 wt % of glycerol to make a binary solvent (80), grating 1 cm³ of 99.4 to 99.9 wt % of Aluminum of 99.95% purity and 0.1 to 0.6 wt % of Indium to make filings (82) with an equivalent surface area of 20 to 30 cm², immersing the filings (82) in 150 to 200 ml of the binary solvent (80) until the filings (82) have dissolved to produce a second electrolyte (64) including third ions (94) containing Aluminum and having a positive charge and including fourth ions (96) containing Aluminum and having a negative charge, wetting the separator (62) with the second electrolyte (64). 